Method of making insulating yarns or rovings



April 1, 1941. w. F. ASTLEY 2,237,267

METHOD OF MAKING INSULATING YARNS OR ROVINGS Fil ed Feb. 14, 1940 .3 Sheets-Sheet l WM XW '47? Wg/A ATTORNEYS.

Apnl 1, 1941. w. F. ASTLEY METHOD OF MAKING INSULATING YARNS OR ROVINGS Filed Feb. s Shets-Sheet 2 INVENTOR. zflz'zzz'm ATTORNEYS q I Apm 1, 1941. w. F. ASTLEY I METHOD onumms INSULATING YARNS OR Rov'mcs 3 Sheets-Sheet 3 Filed Feb. 14, 1940 1/7/0214 :11 tsaau my my w/ m5 J w? at 1 F 62 ATTORNEYS Patented Apr. 1, 1941 METHOD OF MAKING INSULATING YARNS 0R ROVINGS 1 William F. Astley, Cicero, Ill., assignor to Union Asbestos & Rubber Company, Chicago, 111., a' corporation of Illinois Application February 14, 1910, Serial No. 318,795 1 Claim. (61.57-160) The present invention relates to methods of making insulating yarns or rovings, and this application is a continuation-in-part of myprior application, Serial No. 195,117, filed March 10,1938, on Machines for making insulation, which will issue as Patent No. 2,191,875.

The insulating yarns or rovings which are made according to'the present method form a part of the sheet insulation or blankets covered by my prior application, Serial No. 188,720, filed February 4, 1938, on Heat insulating materials and methods of making the same.

Such insulating blankets have marked advantages over the insulation of the prior art in the provision of an insulation of higher efficiency at lower cost, and such materials may be used in all places where flexible or blanket insulation is applicable.

One of the objects of the present invention is the provision of an improved method of making insulating yarn or rovings adapted to be used in constructing improved and highly, efficient insulating material capable of meeting special con-.

ditions, such as use at high temperatures, as, for example, up to 750 or 1,000 F. Another object of the invention is the provision of improved methods for the handling of insu-- lating fibers in the form of asbestos sliver or other loose fibers, and assembling these fibers into an insulating unit yarn or roving of suiiicient strength to maintain its individuality so that it may be coiled and later used in building up an insulating blanket.

Another object of the invention is the provision of an improved method of making a chenille roving -or yarn of asbestos fibers in the form of sliver, or some other fibers, carried by a core yarn or thread, and with or without spirally wound strands in one or both directions about the roving.

Other objects and advantages of the invention will be apparent from the following description and the accompanying drawings, in which similar characters of reference indicate similar parts throughout the several ,views.

Referring to the three sheets of drawings accompanying this specification,

Fig. 1 is a diagrammatic side elevational view of thedelivery side of one form of machine covered by my prior application, mentioned above, and adapted to carry out the method;

Fig. 2 is a fragmentary end 'elevational view of one form of the machine;

Fig. 3 is an enlarged elevational view of the Serial No. 195,117,

improved chenille roving or yarn constructed according to the present method;

Fig. 4 is a sectional view, taken on the plane of the line 4-4 of Fig. 3, looking in the direction of the arrows;

Fig. '5 is a diagrammatic elevational view of the core yarns or threads and the spirally wound yarns or threads;

Fig. 6 is a reproduction of a curve showing the. B. t. u.s per square ft. per inch thickness per hour per degree of Fahrenheit temperature for a blanket constructed of the present chenille rovings or yarns.

The yarns made according to the present invention are to be carefully distinguished from the insulating materials of the prior art employing ropes, frequently called rovings.

One of the most important distinctions between the insulating ropes or yarns of the prior art and the present insulating units is that the fibers of the prior-art devices are twisted in such I manner that the fibers become more unidirectional than the fibers in the presentunit. Being twisted and, aligned with each other, the fibers are more dense and compact in the devices of the prior art, like the strands of a rope.

The rovings or yarns of the prior art also tend to remain separate units when they are assembled side by side in flexible insulation because of their twisted and compacted condition, which is the result of an effort to provide such rovings or yarns with sumcient tensile strength for weaving and maintaining their form in the insulation.

, The insulating yarns or rovings of the present invention have no predetermined shape, and they comprise the carded and open asbestos fibers in the form of sliver," which is the form having the highest volume, the lightest weight, and the greatest insulating valu Referring to Fig. 3, this is an enlarged illustration of an insulating yarn, chenille, or roving constructed according to the invention. It comprises a mass of asbestos fibers 100 in the form of the carded and open sliver, the fibers extending at random in all directions, and projecting from the assembly, which may be indicated by the numeral 10.

These fibers are preferably grouped about one, two, or three core yarns or threads I20, HI, and I22, the number of core yarns depending upon the size of the chenille roving.

I have called my insulating" unit or yarn a chenille roving. for the reason' that its loose fibers. r are assembled about a core yarn, and theypro- 'ect from the yarn at random in various different directions, giving the appearance of a chenille yarn or roving.

In some embodiments of the invention, with a smaller assembly of fibers, only one core yarn I2I may be employed; or, if the assembly is the present material consist of asbestos fibersknown to the trade as Amosite. In this form of the material it is adapted to be used for temperatures up to 750 degrees F. Other fibers which may be similarly treated and used in this material are specially processed mineral wool fibers, such as rock wool in any of its conventional forms, and when the material is constructed with mineral wool it may be usedior temperatures from 750 to 1,000 degrees F.

Sheets or blankets of insulating materials may be constructed according to the present method, including fibers of practically any kind, such as any of the known animal, vegetable, or mineral fibers, including fur, feathers, cotton, wool, linen,

'etc., irrespective of the tensile strength of the fibers when assembled into an insulating unit, because the method of weaving contemplates the use of insulating units having practically no tensile strength, and the threads employed are used primarily for interlacing and securing the fibers together, rather than to provide tensile strength during the weaving operation.

The material is best understood by considering also its mode of manufacture, which will be described briefly. The fibers, such as Amosite asbestos fibers, are first carded, shortened, and fiuffed out, or opened by a carding machine, which may be of conventional construction, except that the fibers in the fiuifed or open condition are deposited upon a conveyor belt, disposed at the bottom of a trough, so that there is a constant stream of the carded and opened fibers coming from the discharge end of the machine.

A plurality of cords, threads, or strands of suitable material are then fed from spools on the machine longitudinally into the stream of opened and carded Amosite fibers, these threads or strands comprising the cords I20, I2I, I22 in Fig. 3. The cords become immersed in the carded and opened fibers and emerge from the machine with it. At the point of discharge from the carding machine it is provided with a special arrangement which is adapted to wrap spirally about the loose Amosite fibers a plurality of insulating cords, such as the cords I23, I24 of Fig. 3, and the cords embrace some of the loose Amosite fibers and bind them to the cords I2III22, but a large portion of the fibers, that is, most of the Amosite fibers, still hang loosely together and project beyond the spiral cords I23, I24 in such manner that the insulating unit of Fig. 3, which is indicated in its entirety by the numeral Ill, isof irregular shape.

It is partially spirally shaped, due to the tightening action of the cords I23; but it has practically no tensile strength for the purpose of weaving, and has only suflicient tensile strength so that it may be coiled in a receptacle, such as a cylindrical can, the can rotating as the insulating unit I0 emerges from the carding and wrapping machine, so that the unit is coiled therein.

, Referring to Figs. 3 and 4, the core yarns I20-I22 and spiral cords or threads I23, I24, used for weaving and wrapping the Amosite or other fibers, preferably comprise a plurality of separate twisted strands. These may be twisted in the same or opposite direction to their own twist, with or without one or more yarns of steel, bronze, or brass in the center as a core for increasing the tensile strength of the cord.

The separate strands of the cords I20-I24 are preferably made of long asbestos fibers capable of withstanding the high temperatures to which the sheet insulation or blanket is to be subjected, and a small amount of cotton or other fiber may be included for improving the weaving characteristics of the fibers used.

Referring to Fig. 5, this is a diagrammatic illustration of the interlacing arrangement of the three internal longitudinal cords and the two spirally wrapped cords. In some embodiments of the invention more or less of these cords may be used, and cords may also be spirally wrapped in opposite direction, if desired, but a minimum amount of such wrapping cords is preferably employed.

In order to illustrate the method of manufacture of the present insulating yarns or chenille rovings, Figs. 1 and 2 are included, showing one type of machine which may be used for. carrying out the method.

It should be understood, however, that the.

fibers and core yarns may be assembled upon a table or any other support, and the fibers and core yarns may be brought into intimate contact with each other by drawing them through a condenser or funnel or other tapered article, or by rubbing the fibers into intimate contact with the core yarns with the hands or otherwise.

Referring to Fig. 1, I0 indicates in its entirety the conventional carding machine, which includes the usual carding cylinders II to I9. The carding machine is adapted to take the fiber or sliver at the right hand end of Fig. 1 and card it, and it is deposited at the left hand side of the carding cylinder I2 in Fig. 1 upon a conveyor belt 20 (Fig.

2), which is disposed in a trough between the carding cylinder I2 and a baflle or side board 22 in such manner that it is adapted to support the amount of carded sliver which is deposited upon the belt 20, and the belt 20 moves toward the right, as indicated by the arrow in Fig. 2, constantly feeding the sliver toward the right in Fig. 2.

The carding machine is provided with one or more, preferably a plurality, of ordinary reels for supporting cords I23, I24, which may be fed into the sliver I0 from the left of Fig. 2 so that the cords I23, I24, which may be provided with thin wires of steel or other suitable material and formed out of asbestos threads, are adapted to be embedded in the sliver and fed toward the right with it after the threads have once been started. At the right hand of the carding machine in Fig. 2 the machine is provided with an attachment, one form of which is shown in Fig. 2.

Referring to Fig. 2, this attachment is mounted It might be expected without a more careful study 01' the operating conditions that the inductance of the coils 9 and it would have a pronounced effect on the shape of the current wave. Such, however, is actually not the case as will be shown from the following illustration. As an example of values which might be encountered in practice, a voltage rise of 1000 kilocycles per mlcrosecond is considered to be aboutthe steepest wave-front and it may be expected to reach its peak in about one microsecond. Assuming that a 10 micro-microfarad capacitor is employed, a current of 10 amperes will flow in the capacitor which will produce a field of approximately 100 persteds inside a coil having 20 turns per inch. Consider now an equivalent sine wave having a frequency of 250 kilocycles per second. In this case, the sine wavewill reach a peak in one microsecond which is the time assumed for the surge voltage under consideration to reach its peak. The reactance of the capacitor would be about 64,000 ohms under such conditions while. the inductance of each of the magnetizing-coils 9 and 10 would be in the order of .2 to 4 microhenries, giving a reactance of only 3 to 6 ohms,

which is obviously negligible as compared to the reactance of the capacitor.

In Fig. 5 I have illustrated diagrammatically an electrical circuit diagram including suitable apparatus which may be employed for measuring the degree of magnetization of the magnetic links used in carrying out my invention. In accordance with the arrangement illustrated, I pro vide'a sensitive moving coil instrument of the d'Arsonval type and substitute the magnetized link to be measured for the usual magnet oithe instrument. Under such couditionsfthehbflection of the instrument pointer-will be proportional both to the degree cr magnetization and the current flowing in the moving eolic'lrcuit of the instrument. It; is obvious then that ii the moving coil current be maintained atsome constant value, the instrument indication will. be proportional to the magnetization of the magnetic link and the scale may be calibratedto read in direct proportion to the maximum rate of change of voltage or the crest value of the current which flows in the capacitor circuit.

Referring more particularly to Fig. 5 of the drawing, I have illustrated a dArsonval type measuring instrument 20 having a scale 2| and a field structure. 22 comprising pole pieces 23 and 24 between which rotates the usual moving coil element 25. The magnetic circuit is arranged to receive one of the magnetic links, such as 9 for example, the degree of magnetization of which is to be measured. A source of unidirectional current 26 may be employed for energizing the moving coil 25 of the instrument. An electrical instrument, such as a milliammeter 21, is preferably connected in the circuit with the moving coil 25 for indicating the magnitude of the current flowing in the moving coil and the r-heostat 28 may also be included in this circuit to provide for adjusting the current to a. predetermined value. An element 29 composed of relatively permeable material may be provided to shield the instrument 20 from extraneous magnetic fields.

The markings on the scale 2| are made proportional to the magnetizing force which is in turn proportional to the magnetizing current and in this case corresponds to the current which flows in the capacitor circuit. The pointer deflection is proportional to the magnetization of the magnetic link. In actual calibration, the markings on the scale may be checked by inserting in the instrument magnetic links which have previously been subjected to known magnetizing i'orces and observing the pointer deflection.

In operating the measuring apparatus 01' Fig. 5 it is necessary only to set the milliammeter current, as indicated by the scale of the instrument 21, at the required value, insert the magneticlink in position in the field structure 22 and obtain the reading from the scale 2| of the m lsuring instrument 20. By the use of such apparatus the degree of magnetization of the link may rapidly be determined with a degree of accuracy whichis satisfactory for the usual system conditions.- I wish to point out that while this particula'rmethod of and apparatus for measuring the magnetization. of the magnetic links commends itself from thegstandpoint of simplicity, it iorms no part of my invention and other well known methods and'apparatus also may be employed.

The advantages obtained in the use of my invention will 'be evident from the following ear- .ample'. Assume-that anelectric power company operating" a transmission line supported by .manytowers' wishes to determine with a mini mum initial capital expenditurefor instruments the maximum'rate of rise or a surge yolta'ge'that may;- be-impressed on the system. This may be accomplished by placing one of the units, such asillustrated in Fig. 2, at each of various points over the system, care being taken to have each magnetic'link suitably marked with some identifying character to indicate the number of the tower arm to which it is adjacent. Only a single measuring instrument, such as illustrated in Fig. 5, is necessary and this may be permanently located in the testing laboratory or suitable location in one of the companys buildings. After the surge is over or at various times a patrolman.

makes a tour of the transmission line system to remove the magnetic link elements to the place where the measuring instrument 20 is located. The magnetic links are then tested in the instrument and a record made or thetower arm number corresponding to. each element and the instrument reading obtained by testing each of the links. After testing, the magnetized elements may be remagnetized to their fullest extent in any suitable manner and they, together with any elements which did not become. demagnetized because they were not subjected toa surge voltage, may be replaced in their original positions and used over again. This may be repeated from time to time by using the same magnetic links over and over again and employing only one instrument to make all the tests.

In accordance with the provisions of the patent statutes, I have described the principles of operation of my invention together with the apparatus which I now consider to represent the best embodiment thereof but I desire to have it understood that the apparatus shown and described is only illustrative and that the invention may be carried out by other means.

What I claim as new and desire to secure by said voltage surge with respect to time, and then measuring the maximum value or said current.

2. The method of measuring the maximum rate of change of a non-recurring voltage wave with assets! netic flux retained by the magnetic element after the occurrence of the surge.

9. In a device for measuring the steepness oi wave-frontof a non-recurring voltage surge, .a

5 respect to time consisting in charging a capacitor capacitor supplied with a voltage proportional to 5 with said voltage, and measuring the maximum said voltage surge, a current conducting, coil value of the charging current oi the condenser. adapted to be energized by a current proportional 3-. The method of measuring the steepness oi to the charg current 0t 8816 pacitor. a mazwave-iront of an electric non-recurring voltage netic element of high magne ic retentivity adapt-- l0 surge, which comprises the steps or demagnetized to be subjected to the magne i field produced ing a permanent magnet by means or a flux de-' y d c il. and m a fo m ur n t e de pe rived from a current proportional to the derivaof magnetization or said magnetic element after tive of the surge voltage wave with respect to he'cccurrence oi the surge.

, time, and then measuring the strength or such 1 a device measuring the m xi um 35 permanent magnet. a rate of rise 9! a non-recurring voltage surge on 15 i. The method of ensuri tmy maximum t an electrical conductor, an electrical circuit comof rise and tall 01 a non-recurring voltage surge p g a capa i r element and n ic flux on an electrical conductor, which comprises de- ECW161118 member adapted t0 b ubject d to riving a current proportional to the first deriva- 531d V e surge, a permanent magnet element tive of said voltage'surge with respect to time, of high magnetic retentivity and initially mag- 20 Influencing t degree a t 'ti of t net'ized substantially to saturation, said permapermanent magnet l t i relatively pponent magnet element being positioned to have its site directions at any instant in accordance with magnetism reduced y the influence Oithe cu e t the magnitude of said current, and thenimeasursaid magnetic flux Producing member, and

- ing the strength of said permanentmagnet means for measuring the residual magnetism of 25 5, Th th f measuring th maximum t said permanent magnet element after the surge of change oi a non-recurring voltage surge with 15 Overrespect to time which comprises deriving a-enr- In a device o measuring e aximum rent from said voltage surge proportional to the rate of Change in the magnitude f & nonecurfirst derivative of said voltage: surge with respect g volta e surge be ore and er e p ak s 0 to time, demagnetizing 9. held of residual magreached, a Capacitor p d w h a voltage pronetism by the influence of said current, and'meas- Portional t0 Said vo tage surge, a plurality of uring t resultant magnetic fle1d netic field producing elements adapted to be en- 6. In a device for determining the steepness of "S by a cur ent proportional to the char ng 5 wave-front of a non-recurring voltage surge on current of said capacitor, a plurality of permaan electrical circuit, a capacitor supplied with a Rent meflnet elements o hi h magnetic retentivvoltage proportional t said voltage surge, and lty, and having an initial residual magnetization means for determining the maximum value or produced by magnetizing force of Sufficient t charging current of t capacitor. value substantiall to saturate the material comm '7. In a device for measuring the maximum rise Posing said magnets- One of said permanent s- 40 and 11 f a non recurring voltage surge on a net elements being arranged to be subjected to conductor, an electrical circuit comprising a cah magnetic field O One i s d field producing 'pacitor adapted to be charged by a voltage proelements, 3 t er of said permanent m portional to said voltage surge, and means in net elements being n e o b ubjected to x circuit with said capacitor for measuring the posithe magne ic field of the other of said field pro- 45 itive and negative crest values of the charging duck! elementsthe arrangement of Said D wurrent of Said dapaciton manent magnet elements relative to said magapparatus for swing a permanent'mdcb netic field producing elements being such that at tion of the steepness or-wave-front of a non-reany i given direction of current 0 curring voltage surge that has occurred on a con- '23: g m g ii 253 223 gz g izf zggiy gg' 1 comprising element posite effects on the induction of said permanent and a magne 151118 member adapted to be magnet elements when compared with the initial liicted to saidvolta e ur a magnetic element polarities or said magnet elements, and means for o high,m 8 re y positioned to be remeasuring the degree of magnetization of said sponsive to the magnetic flux produced by said magnetizin member, and means calibrated with said magnetic element and responsive to the mailpermanent magnet elements aiterthe occurrence 0! said surge.

ROBERT F. EDGAR. 

